1. Field of the Invention
The invention relates to the field of control of industrial apparatus and, more specifically, to error diagnostics in case of an error condition.
2. Description of the Related Art
In an industrial apparatus such as processing equipment, and more particularly in semiconductor and wafer processing equipment, many sensors and actuators are incorporated to sense conditions and execute desired actions. The sensors and actuators are connected to a system controller. Examples of sensors include: temperature sensors, position sensors, pressure sensors, and gas flow sensors. Examples of actuators include: gas valves, pneumatic valves, mass flow controllers, and a thyristor package for firing a heating element. In general, multiple system controllers can be integrated with the processing equipment, each system controller having a certain field of responsibility, such as (i) a temperature controller, taking care of all functions relating to temperature, (ii) a process controller taking care of all functions relating to gas flow, pressure, gas valves etc., and (iii) a motion controller taking care of all functions relating to movement of actuators. In many cases, devices are integrated that have some level of complexity and therefore have their own controller. Such a device controller is then connected to one of the system controllers. Typically, such a device is purchased from a third party supplier, and therefore such devices will be referred to herein generally as “external devices.” Examples include robots for performing motions, such as a wafer handling robot or a cassette handling robot, metrology tools integrated within the processing tool for measuring, e.g., film thickness or surface particle counts, and more complex sensors, such as a sensor for measuring gas concentrations of particular gases (e.g., oxygen or toxic gases).
Typically, the interface between the external device controller and the system controller to which it is connected is an interface designed for normal operation of the processing equipment. The communication enabled by this interface typically supports all functions needed in normal operation. The software of the system controller can be developed such that all normal operation functions of the external device can only be performed when the tool is in such a condition that the function can be executed in a safe manner. This is particularly important in the case of robots, where movements of the robots may cause damage when executed in an unsafe system condition. Examples of such unsafe system conditions include situations where sensors have indicated a wafer is not positioned where expected. Thus, the external device can enter into an error condition.
Often the cause of error conditions, such as motion errors, is not entirely clear and additional information is needed to diagnose and resolve the problem. Usually, this additional information is collected by a field service engineer. For this purpose, the field service engineer generally disconnects the controller of the external device from the system controller to which it is connected and connects a laptop computer directly to the controller of the external device. This procedure entails various drawbacks.
The laptop typically comprises software for diagnostics. Diagnostics commands are typically typed in manually or manually selected from a list of available commands. This takes considerable time.
Furthermore, as the external device is now disconnected from the system controller, the system controller does not check if a command can be executed safely. The safe operation of the diagnostic commands depends largely on the judgment of the individual field service engineer and is prone to human errors.
Another hurdle is that the industrial equipment is generally placed in areas with restricted access, such as clean rooms. Often it is not allowed to enter a laptop computer into such restricted areas or, when allowed, all communication ports on the laptop are sealed off. Special permissions might be required to enter into such a restricted area with a laptop that can be connected to the controller of the external device, causing further delays and equipment downtime. Furthermore, when the field service engineer is finally present at the tool with the error condition, the system has most likely already been brought to a stopped state. The controller of the external device might have, either automatically or by operator intervention, been aborted and internal variables in the registers of the controller might have been cleared, so that a proper diagnostics cannot be made anymore.
It is an objective of the present invention to avoid the problems described above. Accordingly, systems and a method for automated customizable error diagnostics of an error condition in an industrial apparatus are provided.